Abstract Thereisacriticalunmetmedicalneedforarapid,accuratetesttoidentifyAMLpatientswhoarelikelytorespond to chemotherapy. Presently, induction chemotherapy with the DNA damaging drugs cytarabine (ARA-C) and idarubicin(IDR),knownas7+3,isthestandardofcareformostofthesepatients.However,7+3isarelatively ineffectivetherapy,particularlyinolderpatients,andhasserioustherapy-relatedtoxicities.AcceleratedMedical DiagnosticsisdevelopingtheInductDxtesttoidentifythosepatientswhoseAMLwillrespondto7+3induction chemotherapy.Thetestutilizesexvivodiagnosticmicrodoses(~1%ofthetherapeuticdose)of14C-labeled ARA-Cand14C-labeledIDR.Extremelylowlevelsof14Clabelarequantifiedincancercellsisolatedfrompatient bloodsamplesusingacceleratormassspectrometry(AMS).AMSisthemostsensitivetechnologyavailablefor quantifyingradiolabeledcompoundsinbiologicalsamples.Wehypothesizethatathresholdlevelofdrug-DNA damageisrequiredfor7+3efficacy,andthelevelofmicrodose-induceddrug-DNAdamageispredictiveofthe capacity of AML cells to attain that threshold during in vivo chemotherapy. The extent of microdose-induced drug-DNA damage in cell cultures and AML patient samples will be compared with cellular sensitivities and retrospectivepatientresponseto7+3therapyasproof-of-conceptforclinicaldevelopmentoftheInductDxtest forAML.